/* SPDX-License-Identifier: BSD-2-Clause */

/*
 * Copyright (c) 2014 embedded brains GmbH.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <rtems/score/thread.h>
#include <rtems/score/percpu.h>

#ifndef RTEMS_SMP

void __attribute__((naked)) __aeabi_read_tp(void);

void __attribute__((naked)) __aeabi_read_tp(void)
{
  __asm__ volatile (
    "ldr r0, =_Per_CPU_Information\n"
    "ldr r0, [r0, %[executingoff]]\n"
#if defined(__thumb__) && !defined(__thumb2__)
    "add r0, %[threadidoff]\n"
    "ldr r0, [r0]\n"
#else
    "ldr r0, [r0, %[threadidoff]]\n"
#endif
    "bx lr\n"
    :
    : [executingoff] "I" (offsetof(Per_CPU_Control, executing)),
      [threadidoff] "I" (offsetof(Thread_Control, Registers.thread_id))
  );
}

#endif /* RTEMS_SMP */
